In a transistor, the current gain β is defined as: MCQ with Answer and Explanation

In a transistor, the current gain β is defined as:
A. I_E / I_C
B. I_C / I_E
C. I_C / I_B
D. I_B / I_C
Answer: Option C
Solution (By JKExamLibrary)
For a bipolar junction transistor (BJT) in common-emitter configuration, DC current gain β = I_C / I_B, where I_C is collector current, I_B base current. Typical β values range 20-200. Option D is α (common-base gain). Memory tip: 'β = collector current / base current; large β means small base current controls large collector current'. This definition-based question tests electronics fundamentals, frequently examined in competitive exams. Always distinguish β (CE configuration) from α (CB configuration) and their relationship: β = α/(1-α).

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Question #1 Report Error
Light year is unit of:
A. Distance
B. Time
C. Speed
D. Luminosity

Correct Answer: Option A


Explanation:
Light year: distance light travels in one year in vacuum ≈ 9.46×10¹⁵ m. Astronomical distance unit, not time. Memory aid: 'Light year = speed × time = distance'. Unit knowledge frequently tested in competitive exams to avoid common misconception about light year being time unit.

This question belongs to: Science Physics
Question #2 Report Error
One Parsec is a unit of astronomical distance. It is defined as the distance at which a radius of one astronomical unit (AU) subtends an angle of one second of arc. One parsec is approximately equal to:
A. 1.5 x 10^11 meters
B. 3.0 x 10^8 meters
C. 3.26 light years
D. 9.46 x 10^15 meters

Correct Answer: Option C


Explanation:
The parsec (parallax second) is the largest standard unit of distance used in astronomy. 1 Astronomical Unit (AU) is approx 1.5 x 10^11 m. 1 Light Year (ly) is approx 9.46 x 10^15 m. 1 Parsec is approximately 3.08 x 10^16 m. Converting parsecs to light years: (3.08 x 10^16) / (9.46 x 10^15) ≈ 3.26 light years.

This question belongs to: Science Physics
Question #3 Report Error
Weight of 10 kg mass on Moon (g_moon ≈ g_earth/6) is:
A. 100 N
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Correct Answer: Option C


Explanation:
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This question belongs to: Science Physics